Journal of Paleontology, 93(6), 2019, p. 1221–1233 Copyright © 2019, The Paleontological Society. This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/ licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited. 0022-3360/19/1937-2337 doi: 10.1017/jpa.2019.53 New skull remains of Phorusrhacos longissimus (Aves, Cariamiformes) from the Miocene of Argentina: implications for the morphology of Phorusrhacidae Federico J. Degrange,1* Drew Eddy,2,3 Pablo Puerta,4 and Julia Clarke2* 1Centro de Investigaciones en Ciencias de la Tierra (CICTERRA), Universidad Nacional de Córdoba, CONICET, Av. Vélez Sársfield 1611, X5016GCA, Córdoba, Argentina <
[email protected]> 2Department of Geological Sciences, University of Texas at Austin, Austin, Texas 78756, USA <
[email protected]> 3BHP Billiton, 1500 Post Oak Boulevard, Houston, Texas, 77056, USA <
[email protected]> 4Museo Paleontológico Egidio Feruglio, Av. Fontana 140-CP9100, Trelew, Chubut, Argentina <
[email protected]> Abstract.—The giant carnivorous phorusrhacid bird Phorusrhacos longissimus (Aves, Cariamiformes) was first described in 1887 by Florentino Ameghino on the basis of a jaw fragment. The majority of a skull of the species still encased in crumbling rock was preserved only long enough for illustrations to be made by Carlos Ameghino in the field and for a brief description to be written. Skull remains of this species have remained scarce, and few postcranial remains have been figured. Here, we reassess the cranial anatomy of this outstanding ‘terror bird’ species taking into account data from a newly discovered skull.